Murray D, Prager A, Altschuler E M, Brock W A
Department of Experimental Radiotherapy, University of Texas, M.D. Anderson Cancer Center, Houston 77030.
Mutat Res. 1991 Mar;247(1):167-73. doi: 10.1016/0027-5107(91)90044-o.
The effects of the thiols cysteamine, WR-1065, and WR-255591 on radiation-induced micronucleus (MN) frequency and cell killing were compared in cultured Chinese hamster ovary cells. MN were measured using the cytochalasin B assay of Fenech and Morley (1985), which minimizes the effect of cytokinetic perturbations on MN expression. The dose-response curves for MN induction were curvilinear both for control cells at doses between 1.5 and 4.5 Gy and for thiol-treated cells at doses between 3 and 9 Gy. Protection against MN induction by each thiol was independent of radiation dose. Furthermore, there was a close correlation between the degree of modification of MN induction and cell survival by each thiol, i.e., the MN frequency closely predicted the survival level regardless of the presence of absence of the thiols. A similar predictive relationship has also been reported by us for cell survival and DNA double-strand break (DSB) induction in this cell line following treatment with these same thiols. Collectively, these data support the hypothesis that, for DNA-repair-proficient mammalian cells treated with radiomodifying agents that do not alter DNA-repair processes, MN and DSB induction are predictive of the level of radiation lethality and of each other.
在培养的中国仓鼠卵巢细胞中，比较了硫醇半胱胺、WR-1065和WR-255591对辐射诱导的微核（MN）频率和细胞杀伤的影响。使用Fenech和Morley（1985年）的细胞松弛素B试验测量微核，该试验将细胞动力学扰动对微核表达的影响降至最低。对于剂量在1.5至4.5 Gy之间的对照细胞以及剂量在3至9 Gy之间的硫醇处理细胞，微核诱导的剂量反应曲线均为曲线。每种硫醇对微核诱导的保护作用与辐射剂量无关。此外，每种硫醇对微核诱导的修饰程度与细胞存活之间存在密切相关性，即无论是否存在硫醇，微核频率都能密切预测存活水平。我们还报道了在该细胞系中用这些相同的硫醇处理后，细胞存活与DNA双链断裂（DSB）诱导之间存在类似的预测关系。总体而言，这些数据支持以下假设：对于用不改变DNA修复过程的辐射修饰剂处理的DNA修复能力强的哺乳动物细胞，微核和DSB诱导可预测辐射致死水平以及彼此之间的关系。
